This invention relates to novel molding materials capable of exhibiting excellent buffering effect over a wide range of loads and having superior moldability and dimensional stability.
Heretofore, foams of thermoplastic resins such as polystyrene resins, polyvinyl chloride resins, polymethacrylic ester resins and polyolefin resins have been used extensively as buffering material.
However, the buffering character of these resin foams is generally not satisfactory. By way of example, if such resin foam is used as packing material provided with suitable recesses, the packed product is prone to incur such inconvenience as damage caused during transport. Although some resin foams have comparatively good buffering property, the applicable load range is narrow; though superior buffering effect can be exhibited over a certain range of loads, sufficient buffering effect cannot be obtained over the other range of loads. Further, moldability and dimensional stability of the prior art resin foams are poor. Therefore, when they are processed by die pressing, die stamping or the like technique to have complicated shapes or patterns, it will be difficult to obtain a reproduction of exact dimensions and configuration.